Preet Bharara stood out first not for his early prosecutions of bankers and local pols — aggressive, but not unusual for an office with an aggressive tradition — but for his rather edgy sense of humor. It was the summer of 2013, and Preet was the guest of honor at Delivering Alpha, a tony gathering of hedge fund managers.

"You told me there were going to be a lot of people here from the hedge fund industry," Bharara told the room full of suits. "I just want to apologize in advance that I don't have enough subpoenas for all of you."

Pause for nervous laughter.

"Obviously, I'm kidding. I do have enough."

Until fairly recently, it wasn't clear if Preet — he's now a first-name-only New York icon — was just a powerful guy with a weird sense of humor, or whether the attitude that humor implied would extend to his role in what is in some ways the country's most powerful autonomous law enforcement office, the United States attorney for the Southern District of New York. The traditions of prosecutorial independence that Karl Rove once tried and failed to reverse mean that a U.S. attorney doesn't fully answer to the president who appointed him, the party that he belongs to, or really to anyone other than the traditionally pliable foreperson of a federal grand jury. (As a Senate staffer, Bharara played a role in ending the Bush Administration's attempt to control U.S. Attorneys.) And the aggressive, elitist tradition of the Southern District holds that pretty much the entire world is under its jurisdiction.

Bharara's tough talk on Wall Street was followed by action, with the prosecutor finding a technical path around the Justice Department's hesitation to indict a major financial institution.

That move was just a warm-up, it turns out, for a creative and extremely aggressive attack on New York State's two most powerful Democrats. The New York Times scoop Thursday morning that Bharara plans to indict New York State Assembly Speaker Sheldon Silver is a dramatic and unusual move, a step far across the invisible lines that often constrain appointed prosecutors: He has blown up his own political party.

His frontal assault on the open secrets of New York political power has been a genuine shock to the state's politics and even to its press, who missed the secret payments that appear to be at the heart of the reported Silver indictment. The process began last year, when Andrew Cuomo cut a particularly crude variety of the deal on which most statehouses operate: He shut down an ethics investigation into the state legislature in exchange for legislative support for his policies. His gambit became the subject of an excellent Times investigation — and then, to everyone's surprise, Bharara essentially reversed Cuomo's move, using his expansive power to seize the evidence Cuomo's Moreland Commission had gathered and turn it over to his own investigators.

Silver's indictment cites the Moreland Commission files, and notes that Silver had blocked the commission from investigating lawmakers' outside income before shutting it down. Bharara's move has already done massive damage not just to Silver, whose spokesman didn't respond to an email Thursday morning, but also to Cuomo, implicated by extension in a cover-up.

Few saw Bharara's ferocity coming. He had been a federal prosecutor as a young lawyer, as many smart young lawyers are, and then went into politics, serving as a top staffer to Sen. Chuck Schumer, who got him the U.S. attorney job. Schumer doesn't have a particular reputation as a reformer — his interests are meat-and-potatoes policy, not the less visceral questions of governance — and nothing about Bharara's pedigree suggested he planned to burn down the New York State Democratic Party (though nothing suggested any particular loyalty to it either). Bharara was well-liked — funny, media savvy, a live wire — and wasn't known for the kind of raw aggression associated with two other legendary New York prosecutors, Rudy Giuliani and Eliot Spitzer.

Now Bharara is at war, and should he win (and even if he loses — some of Giuliani's Wall Street prosecutions fell apart), he is now an obvious candidate for any of the major New York political offices. And as Mike Bloomberg's allies, in particular, look for a new challenger to Mayor Bill de Blasio, the prosecutor who took on his own party will likely be the first man they call.

Bharara was, briefly, among the figures mentioned last fall for another top job, attorney general of the United States, replacing a loyalist who served as President Obama's "heat shield." Obama went instead with the U.S. attorney for the Eastern District of New York, Loretta Lynch, a well-regarded prosecutor who has not shown the same eagerness to indict prominent Democrats. Bharara, with two more years in office, is that particularly dangerous and rare political figure: a federal prosecutor who doesn't give a fuck.